In the aftermath of Hurricane Sandy, NYC Transit wanted to evaluate the storm surge of a Category 2 hurricane and to perform a conceptual, preliminary and final design of the various components around the perimeter of the 148th Street and 207th Street Yards that are required to prevent floodwater intrusion into each yard and the subway system via the tunnel portal. The components included in the study and design are: perimeter flood walls, waterfront bulkhead and subsurface cutoff walls, flood gate enclosures at driveways, flood gates for tunnel portals, outfall check valves and sealed manholes, sealed regulator chamber, and power supplies.
YU & Associates (YU), as a subconsultant to the prime engineering consultant, provided all geotechnical engineering and related services for this “Sandy Recovery Project” in general conformance with applicable New York State building code and ASCE 7 requirements. Working closely with the prime consultant and NYCT, YU helped to develop the subsurface investigation scope in support of both preliminary and final designs. YU’s work involved relevant information/data search, site reconnaissance, feasibility studies, alternative evaluation, land and offshore subsurface investigation, seepage and stability analyses, liquefaction and seismic analyses, foundation analysis, PLAXIS 3D analysis of bulkhead and platform, geotechnical design reports and budgetary cost estimates.
